In the long term evolution (LTE) system, according to practical situations, a MME might initiate Warning Message Transmission Procedures to an evolved nodeB (eNodeB, eNB) that needs to send a warning message and has established a Si (an interface connecting the MME and the evolved NodeB (eNodeB) in the LTE system) connection with the MME itself so as to notify the eNB to broadcast the warning message to User Equipments (UEs) residing in a relevant area to which the eNB belongs. The warning message mentioned here specifically refers to catastrophic information associated with the earthquake and tsunami warning system (ETWS). Processing of WS information has features of high importance and high timeliness, so as to inform the people in the relevant area timely and effectively to escape before the disaster comes.
According to the description in the 36.413 protocol, a warning message transmission procedure here as shown in FIG. 1 comprises: when there is ETWS related information required to be sent, a MME sends a WRITE-REPLACE WARNING REQUEST message, which contains warning areas in which the eNB is required to broadcast the ETWS information and specific content of the ETWS information, to an eNB. After the eNB completes the processing, it returns a WRITE-REPLACE WARNING RESPONSE message containing a list of areas where broadcast of an information element (IE) with selectable attributes is completed to the MME. It is stated in the 36.413 protocol that if there is no list of areas where broadcast of the IE is completed in the WRITE-REPLACE WARNING RESPONSE message returned by the eNB to the MME, the MME believes that broadcast of the ETWS information in the required warning areas fails. Likewise, if the range indicated by the list of areas, where broadcast of the IE is completed, contained in the WRITE-REPLACE WARNING RESPONSE message returned by the eNB to the MME is smaller than a warning area, where the IE needs to broadcast the ETWS information, contained in the WRITE-REPLACE WARNING REQUEST message returned by the MME to the eNB, the MME believes that broadcast of the ETWS information in the required warning areas fails partially.
Although the 36.413 protocol describes the scenario where broadcast of the ETWS information fails entirely or partially at the MME side, it does not describe the processing after failure. It can be considered that if the MME has known that broadcast of the ETWS information has failed, but it laissez faire without further processing, the ETWS information cannot be timely and effectively notified to all users within areas where broadcast fails such that escape or precaution warnings cannot be sent to the users, thereby going against minimizing huge losses of human life and property when the disaster comes.